The leukemic oncogene tal-2 is expressed in the developing mouse brain

Abstract

tal-1 (T-cell acute leukemia-1; also known as SCL) and tal-2 genes belong to a family of basic helix-loop-helix transcription factors and were originally isolated from the breakpoints of chromosomal translocations in human T-cell leukemia cell lines. tal-1 is expressed not only in hematopoietic cells but also in several endothelial structures and the central nervous system during development. On the other hand, the detailed function and the sites of expression of tal-2 have remained obscure. We cloned the tal-2 cDNA from a mouse embryonic cDNA library and examined its expression pattern in the mouse, comparing with that of tal-1. In situ analyses revealed that tal-2 transcripts are detected at embryonic day 12.5 in the following regions; 1) the diencephalon-the zona limitans intrathalamica and the pretectum, 2) the mesencephalon-the tectum, and the anterior and posterior tegmentum, 3) the metencephalon-the isthmus and the anterior pons. In the diencephalon and the mesencephalon, the expression sites of tal-2 gene were similar to those of tal-1, and its expression was stronger than that of tal-1. In the metencephalon, tal-2 expression was observed in the anterior pons, whereas tal-1 transcripts were detected in the entire pons, and showed stronger expression than tal-2. The tal-2 messages were barely detectable in the brain at birth. These results suggest that tal-1 and tal-2 are involved in the development of specific areas of the central nervous system.

Tal2 expression is induced by all-trans retinoic acid in P19 cells prior to acquisition of neural fate

“…It has been reported that Tal2 expression was observed in embryonic head (E10.5 to E14.5)10. We also confirmed Tal2 expression in embryogenesis (Fig.…”

“…Tal2 is expressed during embryogenesis, and sites of Tal2 expression include specific regions of the diencephalon, mesencephalon and metencephalon10. Tal2 -null mutant mice are viable at birth and initially appear normal.…”

OUT, a Novel Basic Helix-Loop-Helix Transcription Factor with an Id-like Inhibitory Activity

“…A radioactive DNA probe for OUT was prepared by randomprimed labeling of a 1.4-kb PstI-XbaI fragment of the OUT cDNA (nt 398 -1791). Hybridization and washing were performed under high stringency conditions as described previously (56). The full-length glyceraldehyde-3-phosphate dehydrogenase (GAPDH) cDNA was adopted as a probe for an internal loading control.…”

“…essentially as described previously (56). 35 S-Labeled antisense and sense riboprobes were prepared by in vitro transcription with suitable RNA polymerases following linearization of pCMV-OUT (see below) with appropriate restriction enzymes.…”

“…After confirming the sequence, the BamHI-EcoRI fragment was subcloned into the BamHI-EcoRI sites of pCMV to generate pCMV-OUT. Other expression vectors of human E47 (pCMV/SV2-E47; a gift from Ryoichiro Kageyama, Kyoto University), E12 (pSP64-E12; a gift from Eiji Hara), mouse Id2 (pRcCMV-Id2) (57), mouse MyoD (pCMV-MyoD; a gift from Eiji Hara), mouse myogenin (pBS-myogenin; a gift from Shosei Yoshida, Kyoto University), mouse Mash2 (pBSMash2; a gift from François Guillemot, IGBMC, Strasbourg, France), and mouse TAL2 (pmTAL2␣) (56) were constructed by subcloning the cDNA from each plasmid into pCMV with appropriate restriction enzymes, generating pCMV-E47, pCMV-E12, pCMV-Id2, pCMV-MyoD, pCMV-myogenin, pCMV-Mash2, and pCMV-TAL2, respectively.…”